A new, endangered species of canopy tree from the evergreen forests of Ghana and Liberia, Synsepalum ntimii (Sapotaceae)

During forest inventories and conservation-orientated botanic surveys in the 1990s, sterile specimens of an unidentifiable woody plant species turned up from several plots in the Wet Evergreen forests (Hall & Swaine 1981) of SW Ghana. The specimens were from ‘hotspot’ forest rich in known, globally rare species (Hawthorne & Abu Juam 1995) and after extensive searches in herbaria in Europe and Ghana, it seems no specimens of the species had been collected before, at least from Africa, showing that even in a relatively well known tropical forest flora like that of Ghana there is much basic inventory and exploration to be done. Eventually, adults were located by Mr. Ntim Gyakari of Ghana Forestry Department, in Ankasa forest (protected as a National Park) and nearby in Cape Three Points Forest Reserve (F.R.). The earlier sterile specimens did prove to be juveniles of a large canopy tree. In 2002 and 2003 fruiting and flowering material was collected from Cape Three Points F.R. One of the areas in Cape Three Points F.R. that includes the new species and many other rarities has become specially protected by the government of Ghana, as a Globally Significant Biodiversity area (GSBA) where no logging or similar disturbance is allowed (Hawthorne & Abu Juam 1995). The discovery is remarkable because Ghana is relatively well sampled compared to many other tropical countries, and new species of large forest tree are discovered infrequently anywhere is Africa. The new species had been overlooked because: it is clearly rare, even locally; deeply fluted, thus of no commercial interest to loggers; it is easily confused with various other Sapotaceae; its flowers are very inconspicuous; and the ripe fruits seem to be soon eaten by animals. Later, in 2012, the species was found in botanic surveys in Liberia: in Sapo National Park (N.P.) by Jongkind et al.; and independently by the author and colleagues in the same year, nearby in the Putu Hills, where seven individuals were recorded, on the slopes and hilltops of Mt Jideh and Mt Montroh, in an area destined to be mined for Iron Ore. The species was included informally in Hawthorne & Jongkind (2006: 108, 109), but is finally described formally here. The new species is typical of tribe Chrysophylleae with five imbricate sepals, five undivided petals, five stamens and an adaxial seed scar; conforming to parts of Synsepalum (DC) Danniell (both taxa here sensu Pennington 1991), with: rotate corolla (Pradosia type flowers, sensu Pennington loc. cit.: 82); spreading corolla lobes far exceeding the tube; exserted stamens fixed at the top of the corolla tube; minute staminodes; no stipules. It differs from species in the closely related genus Englerophytum A.Chev. by: lacking the distinctive closely striate secondary venation of Englerophytum (although the venation is closer to that pattern than all other known Synsepalum species); lack of stipules; and free filaments. As the seed scar covers less than half the surface of the single seed examined, the new species does not key clearly to Synsepalum nor indeed to any genus in Pennington’s key (1991: 182–184), though the presence or absence of endosperm in the seed and the nature of the cotyledons and radicle is not known, the single mature seed having been